Rotary Laser Level Receiver Circuit ... #2

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RobHalleNL

Joined Oct 25, 2020
4
Right now I plan to use a long string of photodiodes i.e. BP104 like in the photo in the first post in the previous thread, and use those to a) trigger an interrupt on the microcontroller and b) use a latching shift register like 74HC597 to latch and read which photodiode fired. I'm not sure though if the 1µs laser pulse will be strong enough over the ambient daylight to be detected easily. Using a red light filter should help but will it be enough?
Hello Arnold,

The BP104 works from 870 to 1050 nM. Far away from the 635 nM of your transmitter.
Most of the photodiodes has their top around 950 nM.

I have just sended a question to Osram if they have photodiodes working at 635 nM.

I will report their asnwer.
 

Sensacell

Joined Jun 19, 2012
3,500
Great project, but I think you will find it rather difficult.

The signal to noise ratio between ambient light and the laser is going to be really really bad.
Sunlight contains lots of energy at the same wavelength as the laser...
The 10 Hz sweep modulation is way too low to use simple filtering or lock-in techniques, you need a modulated light source that gets you up 'out of the weeds', to a higher frequency where filtering and synchronous demodulation could help.

Not much hope of having a clean logic level to simply send to a shift register.
This will probably require a lot of analog, optical design, and digital signal processing.

I don't want to be a buzzkill, but to encourage you to research and think a lot before you try to build something.

I have yet to see this done on a DIY level.
 
I want to build my own laser-guided grader (using Arduino to control the hydraulics) and the cheapest comparable receivers (with more than 10cm detector area) are around 1000€, and I need 2 of them, so I want to build my own also. I am very interested to hear if anyone (maybe the thread poster?) actually succeeded in building this. I would make a printed PCB and maybe even a batch of 100 or so to share the costs, I'd expect the kit cost to be <100$ each. If anyone is interested please contact me at < mod: deleted email> (but please write a meaningful Subject line as I get lots of spam!)

Mod: Link to old thread
https://forum.allaboutcircuits.com/threads/rotary-laser-level-receiver-circuit.155616/post-1343047
How did it all go, have you found a solution?
 

MisterBill2

Joined Jan 23, 2018
19,364
Another option could possibly be a video camera and software to detect which line the pulse appears in. Certainly a different approach that may possibly be cheaper .
 

waqasah

Joined Mar 5, 2024
4
Another option could possibly be a video camera and software to detect which line the pulse appears in. Certainly a different approach that may possibly be cheaper .
No its not possible as these work in direct sunlight it would be really hard to see the laser
 
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